Self-aligning air bearing for use with servo-track writer

Abstract

A self-aligning air bearing suited to stabilize a rotary structure having a height greater than the width of the structure. A substantially round sleeve is located in a central chamber formed between a mated top and bottom race. An air gland mounted within the sleeve is disposed to receive a journal shaft fixed to the rotary structure, forming an air bearing interface between the shaft and gland when pressurized air is introduced. The sleeve is free within the central chamber to move and align with the axis of rotation of the rotary structure when the air enters the gland but may then be locked into its adopted alignment. The air bearing is particularly useful for supporting a distal end of an extended rotary apparatus in a system for writing servopatterns to the disk surfaces within a plurality of aligned head-disk assemblies (HDAs).

I claim: 
     
       1. A self-aligning air bearing useful for supporting a journal shaft of a rotary apparatus having a center axis of rotation in a servo-track writer (STW) system for writing of servo-information in a plurality of tracks on a plurality of magnetic disk surfaces in a plurality of mounted head-disk assemblies (HDAs), the STW system including air supply means, the self-aligning air bearing comprising: air delivery means coupled to the air supply means for delivering air at a predetermined pressure;   a bottom race having an inner annular shoulder defining upwardly sloping walls and an opening to allow passage of the air delivery means;   a top race configured to mate with the bottom race member, the top race having internal downwardly sloping walls and an opening to allow passage of the air delivery means, the respective sloping walls of the top race and the bottom race forming an internal chamber upon mating;   a sleeve disposed within the internal chamber and having an internal bore and an opening to allow passage of the air delivery means; and   an air gland disposed within the cylindrical bore of the sleeve and having a second bore for receiving the journal shaft therethrough, the second bore having a center axis, the air gland being coupled to the air delivery means and having at least one opening for passing pressurized air into the second bore to create an air film for the substantially frictionless support of the journal shaft as it rotates, wherein the pressurized air causes the air gland and the sleeve to move within the internal chamber until the second bore center axis is aligned to coincide with the center axis of rotation.   
     
     
       2. The self-aligning air bearing of claim 1 further comprising: in the top race, a cup-like shell; and   in the bottom race, a flange for coupling the bottom race to at least one other member of the self-aligning air bearing.   
     
     
       3. The self-aligning air bearing of claim 2 further comprising: a substantially dome-shaped bearing housing disposed over the top race and coupled to the bottom race flange.   
     
     
       4. The self-aligning air bearing of claim 3 further comprising: locking means for applying a locking force to the sleeve to prevent sleeve movement within the internal chamber, thereby fixing the coincident alignment of the second bore center axis with the center axis of journal shaft rotation.   
     
     
       5. The self-aligning air bearing of claim 4 further comprising: in the locking means, a spring-loaded plunger disposed to apply the locking force by applying to the top race a compressive force that is therefrom transmitted to the sleeve.   
     
     
       6. The self-aligning air bearing of claim 2 further comprising: an adapter configured to couple the self-aligning air bearing to the rotary apparatus by providing means for sealing the housing and the top and bottom races, the seating means including means for affording the self-aligning air bearing with a predetermined degree of horizontal planar freedom with respect to the rotary apparatus.   
     
     
       7. The self-aligning air bearing of claim 1 further comprising: in the bottom race, a first substantially conical space defined by the upwardly sloping annular shoulder of the bottom race; and   in the top race, a second substantially conical space defined by the downwardly sloping walls of the top race, wherein the first and second substantially conical spaces together form when mated the internal chamber in which the sleeve moves freely during realignment of the second bore center axis with the center axis of journal shaft rotation.   
     
     
       8. In a servo-track writer (STW) system for writing servo-information simultaneously in a plurality of tracks on a plurality of magnetic disk surfaces in a plurality of aligned head-disk assemblies (HDAs), the STW system including an rotary apparatus for engaging the aligned HDA plurality during a servo-track writing operation, the rotary apparatus having a drive shaft at one end supported on a base bearing defining a center axis of apparatus rotation and having a journal shaft at the other end distal to the drive shaft having a center axis of journal rotation coincident with the center axis of apparatus rotation, the STW system including an air supply and air delivery means for delivering pressurized air at a predetermined pressure, a self-aligning air bearing for supporting the journal shaft distal to the base bearing, the self-aligning air bearing comprising: a bottom race having an inner annular shoulder defining upwardly sloping walls and an opening to allow passage of the air delivery means;   a top race configured to mate with the bottom race member, the top race having internal downwardly sloping walls and an opening to allow passage of the air delivery means, the respective sloping walls of the top race and the bottom race forming an internal chamber upon mating;   a sleeve disposed within the internal chamber and having an internal bore and an opening to allow passage of the air delivery means; and   an air gland disposed within the cylindrical bore of the sleeve and having a second bore for receiving the journal shaft therethrough, the second bore having a center axis, the air gland being coupled to the air delivery means and having at least one opening for passing pressurized air into the second bore to create an air film for the substantially frictionless support of the journal shaft as it rotates, wherein the pressurized air causes the air gland and the sleeve to move within the internal chamber until the second bore center axis is aligned to coincide with the center axis of journal shaft rotation.   
     
     
       9. The self-aligning air bearing of claim 8 further comprising: in the top race, a cup-like shell; and   in the bottom race, a flange for coupling the bottom race to at least one other member of the self-aligning air bearing.   
     
     
       10. The self-aligning air bearing of claim 9 further comprising: a substantially dome-shaped bearing housing disposed over the top race and coupled to the bottom race flange.   
     
     
       11. The self-aligning air bearing of claim 10 further comprising: locking means for applying a locking force to the sleeve to prevent sleeve movement within the internal chamber, thereby fixing the coincident alignment of the second bore center axis with the center axis of journal shaft rotation.   
     
     
       12. The self-aligning air bearing of claim 11 further comprising: in the locking means, a spring-loaded plunger disposed to apply the locking force by applying to the top race a compressive force that is therefrom transmitted to the sleeve.   
     
     
       13. The self-aligning air bearing of claim 9 further comprising: an adapter configured to couple the self-aligning air bearing to the rotary apparatus by providing means for seating the housing and the top and bottom races, the seating means including means for affording the self-aligning air bearing with a predetermined degree of horizontal planar freedom with respect to the rotary apparatus.   
     
     
       14. The self-aligning air bearing of claim 8 further comprising: in the bottom race, a first substantially conical space defined by the upwardly sloping annular shoulder of the bottom race; and   in the top race, a second substantially conical space defined by the downwardly sloping walls of the top race, wherein the first and second substantially conical spaces together form when mated the internal chamber in which the sleeve moves freely during realignment of the second bore center axis with the center axis of journal shaft rotation.   
     
     
       15. A self-aligning air bearing for supporting a journal shaft having an axis of rotation at first end of a rotary apparatus that is supported by a base bearing defining an axis of rotation at a second end distal to the first end, the rotary apparatus including air delivery means coupled to air supply means, the self-aligning air bearing comprising: a bottom race having an inner annular shoulder defining upwardly sloping walls and an opening to allow passage of the air delivery means;   a top race configured to mate with the bottom race member, the top race having internal downwardly sloping walls and an opening to allow passage of the air delivery means, the respective sloping walls of the top race and the bottom race forming an internal chamber upon mating;   a sleeve disposed within the internal chamber and having an internal bore and an opening to allow passage of the air delivery means; and   an air gland disposed within the cylindrical bore of the sleeve and having a second bore for receiving the journal shaft therethrough, the second bore having a center axis, the air gland being coupled to the air delivery means and having at least one opening for passing pressurized air into the second bore to create an air film for the substantially frictionless support of the journal shaft as it rotates, wherein the pressurized air causes the air gland and the sleeve to move within the internal chamber until the second bore center axis is aligned to coincide with the center axis of journal shaft rotation.   
     
     
       16. The self-aligning air bearing of claim 15 further comprising: in the top race, a cup-like shell; and   in the bottom race, a flange for coupling the bottom race to at least one other member of the self-aligning air bearing.   
     
     
       17. The self-aligning air bearing of claim 16 further comprising: a substantially dome-shaped bearing housing disposed over the top race and coupled to the bottom race flange.   
     
     
       18. The self-aligning air bearing of claim 17 further comprising: locking means for applying a locking force to the sleeve to prevent sleeve movement within the internal chamber, thereby fixing the coincident alignment of the second bore center axis with the center axis of journal shaft rotation.   
     
     
       19. The self-aligning air bearing of claim 18 further comprising: in the locking means, a spring-loaded plunger disposed to apply the locking force by applying to the top race a compressive force that is therefrom transmitted to the sleeve.   
     
     
       20. The self-aligning air bearing of claim 16 further comprising: an adapter configured to couple the self-aligning air bearing to the rotary apparatus by providing means for seating the housing and the top and bottom races, the seating means including means for affording the self-aligning air bearing with a predetermined degree of horizontal planar freedom with respect to the rotary apparatus.   
     
     
       21. The self-aligning air bearing of claim 15 further comprising: in the bottom race, a first substantially conical space defined by the upwardly sloping annular shoulder of the bottom race; and   in the top race, a second substantially conical space defined by the downwardly sloping walls of the top race, wherein the first and second substantially conical spaces together form when mated the internal chamber in which the sleeve moves freely during realignment of the second bore center axis with the center axis of journal shaft rotation.